<template>
  <div
    @dragstart.prevent
    :class="[
      'el-input-number',
      inputNumberSize ? 'el-input-number--' + inputNumberSize : '',
      { 'is-disabled': inputNumberDisabled },
      { 'el-da': !!jiajianW },
      { 'is-without-controls': !controls },
      { 'is-controls-right': controlsAtRight },
    ]"
    :style="{ width: width + 'px', height: height + 'px' }"
  >
    <span
      class="el-input-number__decrease decrement"
      role="button"
      v-if="controls"
      v-repeat-click="decrease"
      :class="{ 'is-disabled': minDisabled }"
      :style="{
        width: (jiajianW ? jiajianW : width * 0.2) + 'px',
        height: height - 1.5 + 'px',
        left: (jiajianW ? 1 : 0.5) + 'px',
      }"
      @keydown.enter="decrease"
    >
      <img
        src="./jian.png"
        alt=""
        class="imgjian"
        :style="{
          width: (jiajianW ? jiajianW * 0.5 : width * 0.1) + 'px',
          height: (jiajianW ? jiajianW * 0.5 : width * 0.1) + 'px',
        }"
        v-if="!inputNumberDisabled"
      />
      <img
        src="./Djian.png"
        alt=""
        class="imgjian"
        :style="{
          width: (jiajianW ? jiajianW * 0.5 : width * 0.1) + 'px',
          height: (jiajianW ? jiajianW * 0.5 : width * 0.1) + 'px',
        }"
        v-else
      />
    </span>
    <span
      class="el-input-number__increase increment"
      role="button"
      v-if="controls"
      v-repeat-click="increase"
      :class="{ 'is-disabled': maxDisabled }"
      :style="{
        width: (jiajianW ? jiajianW : width * 0.2) + 'px',
        height: height - 1.5 + 'px',
      }"
      @keydown.enter="increase"
    >
      <img
        src="./jia.png"
        alt=""
        class="imgjian"
        :style="{
          width: (jiajianW ? jiajianW * 0.5 : width * 0.1) + 'px',
          height: (jiajianW ? jiajianW * 0.5 : width * 0.1) + 'px',
        }"
        v-if="!inputNumberDisabled"
      />
      <img
        src="./Djia.png"
        alt=""
        class="imgjian"
        :style="{
          width: (jiajianW ? jiajianW * 0.5 : width * 0.1) + 'px',
          height: (jiajianW ? jiajianW * 0.5 : width * 0.1) + 'px',
        }"
        v-else
      />
    </span>
    <el-input
      :style="{ width: width + 'px', height: height + 'px' }"
      ref="input"
      :value="displayValue"
      :placeholder="placeholder"
      :disabled="inputNumberDisabled"
      :size="inputNumberSize"
      :max="max"
      :min="min"
      :name="name"
      :label="label"
      @keydown.up.native.prevent="increase"
      @keydown.down.native.prevent="decrease"
      @blur="handleBlur"
      @focus="handleFocus"
      @input="handleInput"
      @change="handleInputChange"
    >
    </el-input>
  </div>
</template>
<script>
import ElInput from "element-ui/packages/input";
import Focus from "element-ui/src/mixins/focus";
import RepeatClick from "element-ui/src/directives/repeat-click";

export default {
  name: "InputNumber",
  mixins: [Focus("input")],
  inject: {
    elForm: {
      default: "",
    },
    elFormItem: {
      default: "",
    },
  },
  directives: {
    repeatClick: RepeatClick,
  },
  components: {
    ElInput,
  },
  props: {
    width: {
      type: Number,
      default: 160,
    },
    jiajianW: {
      type: Number,
      default: 0,
    },
    height: {
      type: Number,
      default: 32,
    },
    step: {
      type: Number,
      default: 1,
    },
    stepStrictly: {
      type: Boolean,
      default: false,
    },
    max: {
      type: Number,
      default: Infinity,
    },
    min: {
      type: Number,
      default: -Infinity,
    },
    value: {},
    disabled: Boolean,
    size: String,
    controls: {
      type: Boolean,
      default: true,
    },
    controlsPosition: {
      type: String,
      default: "",
    },
    name: String,
    label: String,
    placeholder: String,
    precision: {
      type: Number,
      validator(val) {
        return val >= 0 && val === parseInt(val, 10);
      },
    },
  },
  data() {
    return {
      currentValue: 0,
      userInput: null,
    };
  },
  watch: {
    value: {
      immediate: true,
      handler(value) {
        let newVal = value === undefined ? value : Number(value);
        if (newVal !== undefined) {
          if (isNaN(newVal)) {
            return;
          }

          if (this.stepStrictly) {
            const stepPrecision = this.getPrecision(this.step);
            const precisionFactor = Math.pow(10, stepPrecision);
            newVal =
              (Math.round(newVal / this.step) * precisionFactor * this.step) /
              precisionFactor;
          }

          if (this.precision !== undefined) {
            newVal = this.toPrecision(newVal, this.precision);
          }
        }
        if (newVal >= this.max) newVal = this.max;
        if (newVal <= this.min) newVal = this.min;
        this.currentValue = newVal;
        this.userInput = null;
        this.$emit("input", newVal);
      },
    },
  },
  computed: {
    minDisabled() {
      return this._decrease(this.value, this.step) < this.min;
    },
    maxDisabled() {
      return this._increase(this.value, this.step) > this.max;
    },
    numPrecision() {
      const { value, step, getPrecision, precision } = this;
      const stepPrecision = getPrecision(step);
      if (precision !== undefined) {
        if (stepPrecision > precision) {
          console.warn(
            "[Element Warn][InputNumber]precision should not be less than the decimal places of step"
          );
        }
        return precision;
      } else {
        return Math.max(getPrecision(value), stepPrecision);
      }
    },
    controlsAtRight() {
      return this.controls && this.controlsPosition === "right";
    },
    _elFormItemSize() {
      return (this.elFormItem || {}).elFormItemSize;
    },
    inputNumberSize() {
      return this.size || this._elFormItemSize || (this.$ELEMENT || {}).size;
    },
    inputNumberDisabled() {
      return this.disabled || !!(this.elForm || {}).disabled;
    },
    displayValue() {
      if (this.userInput !== null) {
        return this.userInput;
      }

      let currentValue = this.currentValue;

      if (typeof currentValue === "number") {
        if (this.stepStrictly) {
          const stepPrecision = this.getPrecision(this.step);
          const precisionFactor = Math.pow(10, stepPrecision);
          currentValue =
            (Math.round(currentValue / this.step) *
              precisionFactor *
              this.step) /
            precisionFactor;
        }

        if (this.precision !== undefined) {
          currentValue = currentValue.toFixed(this.precision);
        }
      }

      return currentValue;
    },
  },
  methods: {
    toPrecision(num, precision) {
      if (precision === undefined) precision = this.numPrecision;
      return parseFloat(
        Math.round(num * Math.pow(10, precision)) / Math.pow(10, precision)
      );
    },
    getPrecision(value) {
      if (value === undefined) return 0;
      const valueString = value.toString();
      const dotPosition = valueString.indexOf(".");
      let precision = 0;
      if (dotPosition !== -1) {
        precision = valueString.length - dotPosition - 1;
      }
      return precision;
    },
    _increase(val, step) {
      if (typeof val !== "number" && val !== undefined)
        return this.currentValue;

      const precisionFactor = Math.pow(10, this.numPrecision);
      // Solve the accuracy problem of JS decimal calculation by converting the value to integer.
      return this.toPrecision(
        (precisionFactor * val + precisionFactor * step) / precisionFactor
      );
    },
    _decrease(val, step) {
      if (typeof val !== "number" && val !== undefined)
        return this.currentValue;

      const precisionFactor = Math.pow(10, this.numPrecision);

      return this.toPrecision(
        (precisionFactor * val - precisionFactor * step) / precisionFactor
      );
    },
    increase() {
      if (this.inputNumberDisabled || this.maxDisabled) return;
      const value = this.value || 0;
      const newVal = this._increase(value, this.step);
      this.setCurrentValue(newVal);
    },
    decrease() {
      if (this.inputNumberDisabled || this.minDisabled) return;
      const value = this.value || 0;
      const newVal = this._decrease(value, this.step);
      this.setCurrentValue(newVal);
    },
    handleBlur(event) {
      this.$emit("blur", event);
    },
    handleFocus(event) {
      this.$emit("focus", event);
    },
    setCurrentValue(newVal) {
      const oldVal = this.currentValue;
      if (typeof newVal === "number" && this.precision !== undefined) {
        newVal = this.toPrecision(newVal, this.precision);
      }
      if (newVal >= this.max) newVal = this.max;
      if (newVal <= this.min) newVal = this.min;
      if (oldVal === newVal) return;
      this.userInput = null;
      this.$emit("input", newVal);
      this.$emit("change", newVal, oldVal);
      this.currentValue = newVal;
    },
    handleInput(value) {
      this.userInput = value;
    },
    handleInputChange(value) {
      const newVal = value === "" ? undefined : Number(value);
      if (!isNaN(newVal) || value === "") {
        this.setCurrentValue(newVal);
      }
      this.userInput = null;
    },
    select() {
      this.$refs.input.select();
    },
  },
  mounted() {
    let innerInput = this.$refs.input.$refs.input;
    innerInput.setAttribute("role", "spinbutton");
    innerInput.setAttribute("aria-valuemax", this.max);
    innerInput.setAttribute("aria-valuemin", this.min);
    innerInput.setAttribute("aria-valuenow", this.currentValue);
    innerInput.setAttribute("aria-disabled", this.inputNumberDisabled);
  },
  updated() {
    if (!this.$refs || !this.$refs.input) return;
    const innerInput = this.$refs.input.$refs.input;
    innerInput.setAttribute("aria-valuenow", this.currentValue);
  },
};
</script>
<style lang="scss" scoped>
.decrement {
  display: flex;
  align-items: center;
  background-color: #add3f1;
  .imgjian {
    object-fit: contain;
    margin: 0 auto;
  }
}
.increment {
  display: flex;
  align-items: center;
  background-color: #add3f1;
  .imgjian {
    object-fit: contain;
    margin: 0 auto;
  }
}
.el-da {
  border: none;
  border: none;
  .el-input-number__decrease,
  .el-input-number__increase {
    top: 1.25px;
  }
}
</style>
